Crystal Polymorphism Induced by Surface Tension
Classical DFT is used to compute surface solid-fluid surface tensions. The results help explain competition between BCC and FCC structures during crystallization.
Classical DFT is used to compute surface solid-fluid surface tensions. The results help explain competition between BCC and FCC structures during crystallization.
Impurities that individually impede crystal growth can paradoxically be less effective when combined.
A theory of nucleation that is able to predict nonclassical pathways and intermediates for crystallization is formulated.
Classical DFT calculations of a liquid droplet attached to a wall. As the temperature is lowered, more and more structure develops until the droplet spontaneously crystallizes.
Crystal surfaces populated with macrosteps continue to grow even when single steps are stopped by surface bound impurities due to a novel mechanism exposed in our simulations: the macrostep facet provides an escape route for single steps to grow in the direction normal to the vicinal face, allowing crystals to break the kinetic barrier of the impurity fence.
Freezing a nanodroplet deposited on a solid substrate leads to the formation of crystalline structures..
Nanoscopic pores are used to attract macromolecules.
Macrosteps can grow under conditions of low supersaturation and high impurity density such that elementary step growth is completely arrested.
Step growth has both deterministic and stochastic regimes
Microscopic observation of nucleation on a surface.
Mesoscopic Nucleation Theory is used to construct a two-variable theory of droplet muceation that reveals non-classical behavior. The figure shows the free energy surface for droplet nucleation with the horizontal and vertical axes being the cluster radius and the density inside the cluster, respectively. The line is the most likely path for droplet nucleation from an initial low-density vapor.
Step growth in the presence of impurities is governed by thermodynamics - not kinetics.